The aim of this research is to present the use and advantages of electro-active eco-fluids as smart biolubricants.Polarizable clay mineral nanoparticles,such as the layered nanosilicate montmorillonite Cloisite 15A an...The aim of this research is to present the use and advantages of electro-active eco-fluids as smart biolubricants.Polarizable clay mineral nanoparticles,such as the layered nanosilicate montmorillonite Cloisite 15A and the fiber-like sepiolite Pangel B20,were dispersed in a sustainable fluid,castor oil,at concentrations of 0.5,2,and 4 wt%.These dispersions exhibit electro-viscous behavior,which was characterized by higher yield stress values with increasing electric field strength.Based on this,the influence of electric potentials was investigated in an electrified axial ball bearing device.The coefficient of friction(COF)was changed as needed and reversibly when different electric fields of 100 and 200 V/mm were applied.A 10.7%increase in the coefficient of friction was observed with a 4 wt%Cloisite 15A in castor oil at 200 V/mm.In the case of Pangel B20,the application of an electric field of 200 V/mm successfully prevented the lubricant from being displaced from the contact zone at 500 r/min.In addition,the dielectric breakdown resistance of these clays was analyzed.Cloisite 15A yielded better results than Pangel B20,probably due to its greater electro-responsive and thus film-forming potential.Finally,the load-carrying capacity was also evaluated.Under the action of an electric field,an opposite vertical force was observed when a ball was pressed onto a plate with a lubricating film in between.Consequently,the study allows conclusions to be drawn about a new lubrication concept based on electro-active control of friction in electrified tribological contacts by fully sustainable electro-rheological(ER)lubricating fluids.展开更多
The effect of galvanically induced potentials on the friction and wear behavior of a 1 RK91 stainless steel regarding to tribocorrosion was investigated using an oscillating ball-on-disk tribometer equipped with an el...The effect of galvanically induced potentials on the friction and wear behavior of a 1 RK91 stainless steel regarding to tribocorrosion was investigated using an oscillating ball-on-disk tribometer equipped with an electrochemical cell. The aim of this investigation is to develop a water-based lubricant. Therefore 1 molar sodium chloride(NaCl) and 1% 1-ethyl-3-methylimidazolium chloride [C_2 mim][Cl] water solutions were used. Tribological performance at two galvanically induced potentials was compared with the non-polarized state: cathodic potential-coupling with pure aluminum- and anodic potential-coupling with pure copper. Frictional and electrochemical response was recorded during the tests. In addition, wear morphology and chemical composition of the steel were analyzed using scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS), respectively. The galvanically induced cathodic polarization of the stainless steel surface results in electrochemical corrosion protection and the formation of a tribolayer. Cations from the electrolyte(sodium Na^+ and 1-ethyl- 3-methylimidazolium [C_2 mim]^+) interact and adhere on the surface. These chemical interactions lead to considerably reduced wear using 1 NaC l(86%) and 1% 1-ethyl-3-methylimidazolium chloride [C_2 mim][Cl](74%) compared to the nonpolarized system. In addition, mechanical and corrosive part of wear was identified using this electrochemical technique. Therefore this method describes a promising method to develop water-based lubricants for technical applications.展开更多
基金research projects sponsored by“Programa Operativo FEDER-Andalucía 2014-2020”(UHU-1255843 and UHU-202008)a"Generación de Conocimiento 2023"project(PID2023-151761NB-100)funded by MICIU/AEI/10.13039/501100011033 and by FEDER,UEsupport.Samuel David Fernández-Silva acknowledges“Ayudas para la Contratación Predoctoral de Personal Investigador en Formación 2021,Junta de Andalucía”(PREDOC_01696),for funding his Ph.D.thesis.In addition,it was in part also supported by Fraunhofer Cluster of Excellence Programmable Materials.
文摘The aim of this research is to present the use and advantages of electro-active eco-fluids as smart biolubricants.Polarizable clay mineral nanoparticles,such as the layered nanosilicate montmorillonite Cloisite 15A and the fiber-like sepiolite Pangel B20,were dispersed in a sustainable fluid,castor oil,at concentrations of 0.5,2,and 4 wt%.These dispersions exhibit electro-viscous behavior,which was characterized by higher yield stress values with increasing electric field strength.Based on this,the influence of electric potentials was investigated in an electrified axial ball bearing device.The coefficient of friction(COF)was changed as needed and reversibly when different electric fields of 100 and 200 V/mm were applied.A 10.7%increase in the coefficient of friction was observed with a 4 wt%Cloisite 15A in castor oil at 200 V/mm.In the case of Pangel B20,the application of an electric field of 200 V/mm successfully prevented the lubricant from being displaced from the contact zone at 500 r/min.In addition,the dielectric breakdown resistance of these clays was analyzed.Cloisite 15A yielded better results than Pangel B20,probably due to its greater electro-responsive and thus film-forming potential.Finally,the load-carrying capacity was also evaluated.Under the action of an electric field,an opposite vertical force was observed when a ball was pressed onto a plate with a lubricating film in between.Consequently,the study allows conclusions to be drawn about a new lubrication concept based on electro-active control of friction in electrified tribological contacts by fully sustainable electro-rheological(ER)lubricating fluids.
基金the he MFW-BW(Ministeriumfür Wirtschaft,Arbeit und Wohnungsbau Baden-Württemberg,Project:BioSis)for funding this project
文摘The effect of galvanically induced potentials on the friction and wear behavior of a 1 RK91 stainless steel regarding to tribocorrosion was investigated using an oscillating ball-on-disk tribometer equipped with an electrochemical cell. The aim of this investigation is to develop a water-based lubricant. Therefore 1 molar sodium chloride(NaCl) and 1% 1-ethyl-3-methylimidazolium chloride [C_2 mim][Cl] water solutions were used. Tribological performance at two galvanically induced potentials was compared with the non-polarized state: cathodic potential-coupling with pure aluminum- and anodic potential-coupling with pure copper. Frictional and electrochemical response was recorded during the tests. In addition, wear morphology and chemical composition of the steel were analyzed using scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS), respectively. The galvanically induced cathodic polarization of the stainless steel surface results in electrochemical corrosion protection and the formation of a tribolayer. Cations from the electrolyte(sodium Na^+ and 1-ethyl- 3-methylimidazolium [C_2 mim]^+) interact and adhere on the surface. These chemical interactions lead to considerably reduced wear using 1 NaC l(86%) and 1% 1-ethyl-3-methylimidazolium chloride [C_2 mim][Cl](74%) compared to the nonpolarized system. In addition, mechanical and corrosive part of wear was identified using this electrochemical technique. Therefore this method describes a promising method to develop water-based lubricants for technical applications.
